package design;

public class leetCode470_rand10 {
    public int rand10() {
        while (true){
            int a = (rand7() - 1) * 7;
            int b = rand7();
            if(a + b <= 40) return (a + b)%10 + 1;
        }
    }
    private int rand7(){
        return 0;
    }
}
